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Öğe Circulating leptin, zinc, and copper levels after extracorporeal circulation(MAGHIRA & MAAS PUBLICATIONS, 2005) Gormus, ZI; Gormus, N; Baltaci, AK; Halifeoglu, I; Mogulkoc, ROBJECTIVE: The role of leptin in the acute stress response to extracorporeal circulation has been well documented, however, the relationship between leptin and zinc has not been investigated previously. We aimed to research the circulating leptin, zinc, and copper levels before, during, and after the extracorporeal circulation, and effect of preoperative zinc administration to these. METHODS: Twenty patients who were taken to elective coronary artery bypass grafting operations using extracorporeal circulation were taken to this research and divided into two equal groups (n(1), n(2)). In both groups blood samples were taken just before the operation (T0), at the end of operation (T1), and at the first postoperative day (T2). In the second group (n(2)) oral zinc (50 mg, once a day) was administered to patients for 5 days, preoperatively. The serum leptin, zinc, and copper levels were studied. RESULTS: In group n(1) circulating leptin levels were significantly increased at T2 when compared to T0 and T1 (p < 0.05); zinc levels were decreased at T2 when compared to T0 and T1 (p < 0.05); copper levels were decreased at T2 when compared to T0 (p < 0.05), and decreased at T1 when compared to T0 (p < 0.05). In group n(2) circulating leptin levels were significantly increased at T2 when compared to T0 and T1 (p < 0.05); zinc levels were decreased at T2 when compared to T0 and T1 (p < 0.05); copper levels were increased at T2 when compared to T1 (p < 0.05). CONCLUSIONS: These results indicate that circulating leptin levels increase after the extracorporeal circulation as an acute response, while zinc and copper levels decrease at the same period. Preoperative zinc administration does not prevent the leptin response after extracorporeal circulation.Öğe The effect of leptin on penicillin-induced epileptiform activity in rats(PERGAMON-ELSEVIER SCIENCE LTD, 2006) Ayyildiz, M; Yildirim, M; Agar, E; Baltaci, AKLeptin is an adipose tissue-derived peptide hormone, which acts as a satiety factor to reduce appetite by interactions with hypothalamic neurons. The other possible physiological functions of leptin are still unclear. In this study, we have evaluated dose-dependent effect of leptin on penicillin-induced epileptiform activity, analyzed by electrocorticogram (ECoG). The epileptiform activity was induced by microinjection of penicillin into the left sensorymotor cortex. Thirty minutes after penicillin injection, 1, 2 or 10 mu g of leptin was administrated intracerebroventricularly (i.c.v.). Leptin (1, 2 or 10 mu g) alone did not significantly change the spike amplitudes in non-penicillin pretreated control animals. One or two micrograms of leptin significantly increased the frequency of epileptiform activity in the penicillin-pretreated animals. The high dose of leptin (10 mu g) did not significantly change either amplitude or frequency of epileptiform activity. One microgram i.c.v. leptin was the most effective dose in changing of frequency on penicillin-induced epileptiform activity. The proconvulsant effects of leptin appeared 90 min after leptin (I and 2 jig) injection. These data indicate that leptin increases the frequency of penicillin-induced epileptic activity. We speculate that this action of leptin might suggest that leptin may be a proconvulsant substance. 2005 Elsevier Inc. All rights reserved.Öğe The effect of pinealectomy and zinc deficiency on nitric oxide levels in rats with induced Toxoplasma gondii infection(E M H SWISS MEDICAL PUBLISHERS LTD, 2004) Baltaci, AK; Mogulkoc, R; Turkoz, Y; Bediz, CS; Ozugurlu, FPrinciples: This study aims at investigating how zinc deficiency and pinealectomy affect nitric oxide levels in rats infected by Toxoplasma gondii. Methods: The study was conducted on a total of 50 adult, male rats of Spraque-Dawley species. The study groups were as follows: General, intact control group (Group I, n = 10), infected control group (Group II, n = 10), infected and zinc-deficient group (Group III, n = 10), infected and pincalectomized group (Group IV, n = 10), infected, zinc-deficient and pinealectomized group (Group V, n = 10). After the experiment the rats were decapitated and levels of zinc, melatonin and total nitrite were identified in the blood samples collected. Results: The total nitrite levels in groups TV and V were more than those in all other groups (p <0.01). The total nitrite levels in Group II were also higher than those in Groups I and III (p <0.01). Plasma zinc levels in the zinc-deficient group and zinc-deficient and pinealectomized group were lower than those in all other groups, while melatonin levels were lower in Infected pinealectomized group (Group IV) and infected, zinc-deficient and pinealectomized group (Group V) than all others (p <0.01). Conclusions: The present study shows that plasma nitric oxide levels increase during Toxoplasma gondii infection, but this increase becomes more apparent in the presence of melatonin deficiency and is inhibited by zinc deficiency.Öğe Effect of zinc deficiency and supplementation on lipid peroxidation of renal tissue in ovariectomized rats(HUMANA PRESS INC, 2004) Baltaci, AK; Sunar, F; Mogulkoc, R; Oztekin, EThe aim of this study was to investigate how zinc deficiency and supplementation affects lipid peroxidation in the renal tissue in ovariectomized rats. Four study groups were formed with 10 Spraque-Dawley rats each. Two of the groups served as normal and ovariectomized controls; the other two were ovariectomized rats that were zinc deficient and zinc supplemented, respectively. The zinc-deficient ovariectomized rats showed greater renal and plasma lipid peroxidation, as indicated by higher malondialdehyde levels than all other groups (p<0.05). These values were higher in the ovariectomized controls than those of the normal controls and of the ovariectomized, zinc-supplemented groups (p<0.05), which, in, turn, showed no significant differences of their respective renal and plasma malondialdehyde values. The renal and erythrocyte glutathione levels in the zinc-supplemented rats were higher than those in all other groups (p<0.05). The zinc-deficient group had the lowest renal and erythrocyte glutathione levels (p<0.05). The renal tissue zinc levels in the ovariectomized rats were higher than those in the zinc-deficient animals, but lower than in the normal controls and zinc-supplemented rats (p<0.05). The zinc-supplemented animals had the highest renal tissue zinc levels (p<0.05). The results of this study suggest that zinc deficiency increases renal tissue damage in ovariectomized rats and that zinc supplementation can be used to prevent this condition.Öğe Effect of zinc supplementation on hematological parameters in athletes(HUMANA PRESS INC, 2004) Kilic, M; Baltaci, AK; Gunay, MThe hematological effects of oral supplementation of zinc to training athletes are reported in the present study. A total of 30 subjects between 16 and 22 yr of age volunteered to participate in a 4-wk study They were equally divided into three groups. Group I acted as resting controls receiving daily doses of 3 mg Zn/kg body wt. Group 2 was actively engaged in wrestling and exercised for 90-120 min, 5 d a week. Group 3 was also actively engaged in wrestling and exercised for 90-120 min, 5 d a week, but they were supplemented with 3 mg Zn/kg body wt per day. The erythrocyte, leukocyte, and thrombocyte counts and the hemoglobin values of all subjects participating in the study were measured before and after exercise at the beginning and at the end of the 4-wk study period. In all groups, there were no significant differences in the measured parameters before and after exercise. At the end of the supplementation period, the parameters of the subjects in groups 1 and 3 were significantly higher than those of group 2, both before (p<0.005) and after (p<0.05) exercise. These results suggest that zinc supplementation has a positive effect on hematological parameters in athletes.Öğe Effects of maternal deprivation on melatonin production and cognition in adolescent male and female rats(MAGHIRA & MAAS PUBLICATIONS, 2005) Uysal, N; Ozdemir, D; Dayi, A; Yalaz, G; Baltaci, AK; Bediz, CSOBJECTIVES: It is known that maternal deprivation (MD) may alter cognitive functions such as learning and memory in adult life by effecting normal growth and development. However, the mechanisms of these cognitive alterations are unknown. The aim of this study is to investigate the effects of maternal deprivation on cognition and melatonin production in adolescent male and female rats. METHODS: The litters were separated daily from their mothers for 6 hours on postnatal days 2 to 20. The spatial memory performance was evaluated using a Morris water maze between the postnatal 26th and 32nd days. Plasma melatonin levels were determined on postnatal days 42. RESULTS: MD-rats had longer escape latencies at the second, third and fifth days of training days and spend significantly less time in probe trial, compared to control animals. MAIN FINDINGS: The repeated maternal deprivation caused low blood melatonin levels and there was a significant negative correlation between blood melatonin levels and spatial memory performance in both of male and female adolescent rats. CONCLUSION: These results suggest an association between melatonin production and neurodevelopment. Further studies are needed to determine the interaction between maternal deprivation and pineal gland maturation/function.Öğe Effects of trace element levels on platelet aggregation(HUMANA PRESS INC, 2004) Kurtoglu, E; Ugur, A; Baltaci, AK; Halifeoglu, IPlatelet aggregation was measured by an optical method in 32 patients with iron-deficiency anemia at the time of diagnosis and after a period of Supplementation with iron. Epinephrine- and adenosine diphosphate-induced platelet aggregation were lower in anemic patients than in the controls (p<0.05). After iron-supplementation therapy, these values showed no significant differences. If induced by collagen or ristocetin, platelet aggregation was the same for patients and controls, but increased after treatment of patients (p<0.05). The plasma zinc values did not show significant differences among the subjects included in this study. These results show that iron is involved in the enzymatic systems that regulate platelet aggregation. The exact nature of this interaction is still to be determined.Öğe Effects of zinc deficiency and pinealectomy on cellular immunity in rats infected with Toxoplasma gondii(HUMANA PRESS INC, 2005) Baltaci, AK; Mogulkoc, R; Bediz, CS; Pekel, AThe effects of zinc and/or melatonin deficiencies on cellular immunity were investigated in rats infected with Toxoplasma gondii. A total of 50 adult male Sprague-Dawley rats were divided into 5 groups of 10 rats each. In group 1, the rats were infected with T gondii and fed a zinc-deficient diet; in group 11, the rats were infected and their pineal gland was surgically removed. Group III included rats that were infected, pinealectomized, and fed a zinc-deficient diet. Group IV consisted of T gondii-infested rats that received no treatment of any kind, and group V were normal controls. After 3 wk of treatment, all rats were sacrificed and the percentages of CD3, CD4, and CD8 lymphocytes, zinc, and melatonin levels in plasma and the percentage of lymphocyte in blood smears were analyzed. The CD3 ratios of groups I-III were significantly lower than those of groups IV and V (p<0.01). The CD4 lymphocytes were significantly higher in group TV than that in all other groups (p<0.05). In group IV, the CD8 lymphocytes were higher than in groups I-III (p<0.01) and those in group V were higher than for groups I and III (p<0.01). Lymphocyte incidence in group IV was higher than in the other four groups (p<0.01). The plasma zinc and plasma melatonin levels in groups I-III were significantly lower than those in the controls (p<0.01, both cases). These results suggest that zinc and/or melatonin deficiency have a negative influence on cellular immunity in rats with toxoplasmosis.Öğe The effects of zinc deficiency and supplementation on lipid peroxidation in bone tissue of ovariectomized rats(ELSEVIER SCI IRELAND LTD, 2004) Baltaci, AK; Sunar, F; Mogulkoc, R; Oztekin, EThis study aims at investigating how zinc deficiency and zinc application affect lipid peroxidation in bone tissue of ovariectomized rats. The study included 40 adult female rats of Sprague-Dawley species. Group 1 (n = 10): control group were fed with normal diet. Group 2 (n = 10): the group fed with normal diet after being ovariectomized. Group 3 (n = 10): the group fed with zinc-deficient diet for 6 weeks after ovariectomy. Group 4 (n = 10): the group which was given intraperitoneal zinc (3 mg/kg day zinc) in addition to normal diet for 6 weeks after ovariectomy. Malondialdehyde (MDA) and glutathione (GSH) levels were determined in erythrocyte, plasma and bone tissue. Group 3 had the highest plasma MDA levels compared to Groups 1, 2 and 4 (P < 0.05). These values were higher in Group 2 than in Groups 1 and 4 (P < 0.05). Bone and plasma MDA levels in Groups I and 4 were not different. Bone and erythrocyte GSH levels in Group 4 were higher than those in all other groups (P < 0.05). The lowest levels of bone and erythrocyte GSH levels were observed in Group 3 (P < 0.05). These values were higher in Group 2 when compared to those in Groups I and 3 (P < 0.05). This study demonstrate that zinc deficiency increased bone tissue damage in ovariectomized rats and that zinc supplementation prevented this damage. (C) 2004 Elsevier Ireland Ltd. All rights reserved.Öğe Effects of zinc deficiency and supplementation on plasma leptin levels in rats(HUMANA PRESS INC, 2005) Baltaci, AK; Mogulkoc, R; Halifeoglu, IThe effects of zinc deficiency and supplementation on plasma leptin levels were studied in Sprague-Dawley rats. After 6 wk on a zinc-deficient diet containing 0.65 ppm Zn/g, the mean body weight was significantly lower than that of normal or zinc-supplemented rats, which showed no difference among them. The plasma leptin and zinc levels were lowest in zinc-deficient animals and highest in those that received a normal diet and daily intraperitioneal injections of 3 mg Zn/kg. These results indicate that zinc deficiency leads to a significant inhibition in plasma leptin levels, whereas zinc supplementation significantly increases plasma leptin.Öğe The effects of zinc deficiency and testosterone supplementation on leptin levels in castrated rats and their relation with LH, FSH and testosterone(MAGHIRA & MAAS PUBLICATIONS, 2005) Ozturk, A; Baltaci, AK; Mogulkoc, R; Oztekin, E; Kul, AAIM: The aim of this study was to investigate how zinc-deficiency and testosterone supplementation, both in combination and individually, affect plasma LH, FSH and leptin levels in castrated rats. DESIGN: Group 1, Control Group. Group 2, Castration Group. Group 3, Testosterone Group. Group 4, Zinc-deficient Group. Group 5, Testosterone, Zinc-deficient Group. Group 6, Zinc-deficient, Castration Group. Group 7, Testosterone, Castration Group. Group 8, Zinc-deficient, Testosterone, Castration Group. MEASUREMENTS: Plasma zinc, leptin, LH, FSH, free and total testosterone levels were measured. RESULTS: Group 2 had the highest levels of leptin and LH, besides having the highest FSH levels together with Group 6 (p < 0.01). Groups 5 and 8 had the lowest leptin levels (p < 0.01). Leptin levels in Groups 4 and 7 were higher than those in Groups 5 and 8, but lower than those in all other groups (p < 0.01). LH levels in Group 4 were not different than those in Groups 3, 5 and 8, but significantly lower than those in all other groups (p < 0.01). Free and total testosterone levels were higher in Group 4 than in castration groups that were not supplemented testosterone, but were lower in the former than in all others (p < 0.01). CONCLUSION: Plasma LH may be more effective than testosterone on plasma leptin and zinc can be an important mediator of the effect LH exercises on leptin.Öğe Etanercept treatment in the endotoxin-induced uveitis of rats(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2004) Avunduk, MC; Avunduk, AM; Oztekin, E; Baltaci, AK; Ozyazgan, Y; Mogolkoc, RThis study was conducted to investigate therapeutic value of a soluble tumor necrosis factor-alpha (TNF-alpha) receptor, etanercept, in a rat model of endotoxin-induced uveitis (EIU). Forty-two inbred male Lewis rats were divided into seven equal groups. 200 mug of Escherichia coli 055:1355 lipopolysaccharide, (LPS) was injected in one hind footpad of the Groups 2, 3, 4, 5, 6, and 7 rats. Group 5, 6, and 7 rats also received subcutaneous etanercept 24 hr prior to LPS injection at a dose of 0(.)4 mg kg(-1). Group 1 rats were used as controls. Eight, 24, and 48 hr after treatment clinical uvetis scores (miosis, iris hyperemia, and hypopyon) were assessed by a masked observer and the rats were euthanized. Neutrophil leukocytes, CD8 +, CD4 +, and CD45RO + cells in the anterior uveal tissue were counted either after hematoxylin-eosin or monoclonal antibody staining. TNF-alpha. levels were also measured in the aqueous humor samples by an ELISA method. Etanercept treatment significantly improved clinical uveitis scores at all examination points compared to the LPS injected animals. The improvement was almost complete expect for the miosis score, since no significant difference was detected between the controls and LPS + Etanercept treated animals at all examination points. Cell counts were also at significantly lower levels in LPS + Etanercept treated animals at all examination points, except for CD8 + and CD45RO + cell counts at 24 hr examination point. There was no significant difference between the controls and LPS + Etanercept treated animals at all examination points as with CD4 + and CD45RO + cell counts at 48 hr. Our data showed that etanercept had a definite effect on the treatment of EIU. Further studies should clarify its efficacy on clinical uveitis conditions. (C) 2004 Elsevier Ltd. All rights reserved.Öğe Histological examination of various tissues in rats with hypothyroidism induced by propylthiouracil or thyroidectomy(LIPPINCOTT WILLIAMS & WILKINS, 1999) Mogulkoc, R; Canpolat, L; Baltaci, AK; Yilmaz, B; Kelestimur, HDespite the common use of propylthiouracil (PTU) to induce hypothyroidism, it causes degeneration of the thyroid gland, kidney and anterior pituitary tissue. The aim of our study was to determine changes in the liver, thyroid gland, kidney and anterior pituitary from male rats treated with PTU (10 mg/kg/day; for 2 weeks) and in thyroidectomy-induced hypothyroid male rats. Histological examination was performed by light microscopy. Total T3 and T4 levels were determined by radioimmunassay. In both PTU-treated and thyroidectomized groups, plasma T3 and T4 levels were significantly lower than those in the control group. No abnormal changes were observed in the liver tis sue of the hypothyroid rats. There were significant decreases in the epithelial magnitude of degenerated follicular cells in the thyroid tissues of the PTU-treated animals. Furthermore, these were seen in the lumen, which did not contain colloid. There was mononuclear cell infiltration and haemorrhage in the kidney cortex and medulla in both the thyroidectomized and PTU groups. The anterior pituitary in the thyroidectomized and PTU-treated rats showed a diffused hyperplasia. The tissue was locally haemorrhagic, and basophilic cells were frequently localized at the side of the haemorrhage. These findings show that both PTU and thyroidectomy-induced hypothyroidism causes changes in the histology of the kidney, thyroid gland and anterior pituitary. Med Sci Res 27:801-805 (C) 1999 Lippincott Williams & Wilkins.Öğe Hyperthyroidism causes lipid peroxidation in kidney and testis tissues of rats: Protective role of melatonin(MAGHIRA & MAAS PUBLICATIONS, 2005) Mogulkoc, R; Baltaci, AK; Oztekin, E; Aydin, L; Tuncer, IOBJECTIVE: The present study aimed at determining how 3-weeks intraperitoneal melatonin administration affected oxidative stress caused by experimental hyperthyroidism. MATERIALS AND METHODS: The study was conducted on 30 male rats of Spraque-Dawley species. The experimental animals were divided to 3 groups (control, hyperthyroidism and hyperthyroidism+melatonin). The supplementation was continued for 3 weeks after which the animals were sacrified and tissue malondyaldehyde (MDA) and glutathione (GSH) levels were determined. RESULTS: MDA levels in kidney and testis tissues in hyperthyroidism group were higher than those in control and hyperthyroidism+melatonin administered groups (p < 0.001) and levels in hyperthyroidism + melatonin administered group were higher than those in the control group (p < 0.001). The highest GSH levels were obtained in hyperthyroidism + melatonin-administered group (p < 0.001) and GSH levels in hyperthyroidism group were higher than those in the control group (p < 0.001). CONCLUSION: Results of the study demonstrate that hyperthyroidism induced by 3-weeks L-thyroxine administration increased oxidative stress in kidney and testis tissues and that although melatonin administration inhibited this stress to a certain extent, it could not bring the stress down to the level in controls.Öğe Investigation of serum leptin levels in professional male football players and healthy sedentary males(MAGHIRA & MAAS PUBLICATIONS, 2005) Unal, M; Unal, DO; Baltaci, AK; Mogulkoc, R; Kayserilioglu, AOBJECTIVE: In the present study we aimed at investigating leptin levels in professional male athletes who have been exercising regularly for a long time and leptin levels in healthy sedentary males. METHODS: The study included 10 male professional football players and 17 healthy sedentary males. The relations between groups in terms of leptin levels, Max VO2 levels, blood lactic acid levels before and after exercise and effort durations were investigated. RESULTS: It was found in the study that although BMI of professional male athletes was higher than that of the healthy sedentary males, leptin levels of the former were significantly lower (p < 0.01), while VO(2)Max levels (p < 0.05) and test periods (p < 0.01) were significantly higher than those in the latter. As for lactic acid levels after exercise and between groups, these were also higher in athletes, but the difference was not statistically significant (p > 0.05). CONCLUSION: Leptin levels of those who exercised regularly were found lower than the levels in healthy males. Although the increase in serum leptin levels is in direct proportion with BMI in general, the major determinant of serum leptin level is the body fat rate. As regular exercising reduces body tat rate, it also reduces serum leptin levels.Öğe Melatonin prevents oxidant damage in various tissues of rats with hyperthyroidism(PERGAMON-ELSEVIER SCIENCE LTD, 2006) Mogulkoc, R; Baltaci, AK; Oztekin, E; Aydin, L; Sivrikaya, AImpairment of thyroid functions brings about pathological changes in different organs of body. Findings of in vivo and in vitro studies indicate that thyroid hormones have a considerable impact on oxidative stress. Melatonin reduces oxidative damage through its free radical eliminating and direct anti-oxidant effects. The present study was undertaken to determine how a 3-week period of intraperitoneal melatonin administration affected oxidative damage caused in experimental hyperthyroidism in rat. The experimental animals were divided into 3 groups (control, hyperthyroidism, hyperthyroidism+melatonin). Malondialdehyde (MDA) and glutathione (GSH) levels were determined in different tissues. MDA levels in cerebral, liver and cardiac tissues in hyperthyroidism group were significantly higher than those in control and hyperthyroidism+melatonin supplemented groups (p < 0.001). The highest GSH levels were observed in the group that was administered melatonin in addition to having hyperthyroidism (p < 0.001). These results show that hyperthyroidism increased oxidative damage in cerebral, hepatic and cardiac tissues of rat. Melatonin supplementation may also suppress oxidative damage. (c) 2006 Elsevier Inc. All rights reserved.Öğe Melatonin supplementation to rats subjected to acute swimming exercise: Its effect on plasma lactate levels and relation with zinc(MAGHIRA & MAAS PUBLICATIONS, 2006) Kaya, O; Gokdemir, K; Kilic, M; Baltaci, AKOBJECTIVE: The objective of the present study is to examine the effect on melatonin supplementation on plasma lactate levels and its relation with zinc in rats subjected to acute swimming exercise. METHODS:Thirty adult male rats of Spraque-Dawley species were allocated to 3 groups, each containing an equal number of rats: general control group which was not subjected to any procedure (Group 1), the group which was subjected to 30 minutes acute swimming exercise (Group 2), and the group which was subjected to 30 minutes acute swimming exercise after 4-week intraperitoneal (i.p.) melatonin (3 mg/kg/day) supplementation. Lactate and zinc levels in the plasma were studied in the blood samples taken from the experimental animals by decapitation method. RESULTS:The animals in the control group, which was not subjected to any procedure (group 1), had higher lactate levels than those in groups 2 and 3 (p < 0,05). Lactate levels in the swimming group supplemented with melatonin (group 3) were lower than those in group 2 (swimming group) (p < 0,05). The highest plasma zinc levels were obtained in the melatonin-supplemented swimming group (group 3) (p < 0,05). Group 2 (swimming control) had the lowest plasma zinc levels (p < 0,05). CONCLUSION:Results of the study demonstrate that melatonin supplementation to rats subjected to acute swimming exercise reduces lactate levels, thereby delaying exhaustion. Increased zinc levels may be mediating this melatonin effect.Öğe Opposite effects of zinc and melatonin on thyroid hormones in rats(ELSEVIER IRELAND LTD, 2004) Baltaci, AK; Mogulkoc, R; Kul, A; Bediz, CS; Ugur, AThe present study was conducted to investigate how thyroid function in rats is affected by administration of 3 mg per kg per day of zinc and/or melatonin. The study was conducted with 40 Sprague-Dawley adult male rats equally divided into four groups: 1 (controls), 2 (zinc-only), 3 (melatonin-only) and 4 (zinc- and melatonin-supplemented). The supplementation was continued for 4 weeks after which the animals were sacrificed and plasma samples were obtained for determination of zinc, melatonin, free- and total triiodothyronine (T3), thyroxine (T4) and thyroid-stimulating hormone (TSH) levels. The free T3, T4 and TSH levels were lower in the melatonin group than in all other groups (P<0.01), while free- and total T3 levels were higher in the zinc group (P<0.01). The group that received zinc and melatonin combined had free thyroid hormone levels higher than the only melatonin group. These results show that melatonin has a thyroid function suppressing action, just the opposite to the actions of zinc. When zinc is administered along with melatonin, its thyroid function suppression is diminished. (C) 2003 Elsevier Ireland Ltd. All rights reserved.Öğe Pinealectomy inhibits antioxidant system in rats with hyperthyroidism(MAGHIRA & MAAS PUBLICATIONS, 2005) Mogulkoc, R; Baltaci, AK; Aydin, L; Oztekin, E; Sivrikaya, AOBJECTIVE: Thyroid hormones regulate energy metabolism and act on the mitochondria, which is an important source of free radicals in the cell. Reactive oxygen types play a significant role in physiological mechanisms, but in excessive amounts they can cause oxidative damage in molecules. The aim of the present study was to determine levels of lipid peroxidation caused by induced hyperthyroidism in cerebral, hepatic and cardiac tissues of pinealectomized rats. METHODS: Experimental animals used in the study were allocated to three groups as general control group, hyperthyroidism-sham pinealectomy group and hyperthyroidism-pinealectomy group. GSH and MDA levels in cerebral, hepatic and cardiac tissues were evaluated at the end of the 3-week study period. RESULTS: It was found that MDA levels in cerebral, hepatic and cardiac tissues were the highest in hyperthyroidism and pinealectomy group and that these values were higher in hyperthyroidism-sham pinealectomy group than in the control group (p < 0.001). it was seen that tissue GSH levels significantly increased in hyperthyroidism-sham pinealectomy group (p < 0.001) and that the increase in hyperthyroidism and pinealectomy group was higher than the increase in the control group only (p < 0.001). CONCLUSION: Results of our study show that MDA and GSH levels in cerebral, hepatic and cardiac tissues increased due to hyperthyroidism and that the increase in MDA levels became more evident and GSH levels were significantly suppressed after pinealectomy.Öğe The relation between serum leptin levels and max VO2 in male patients with type I diabetes and healthy sedentary males(TAYLOR & FRANCIS INC, 2004) Unal, M; Unal, DO; Salman, F; Baltaci, AK; Mogulkoc, RThis study aimed at investigating leptin levels in male diabetes type I patients who were on insulin treatment and also healthy sedentary males. The study included 10 male type I diabetes patients and 17 healthy sedentary males. Leptin levels of type I diabetes patients and healthy sedentary males with body mass index (BMI) over 25 kg/m(2) were evaluated separately. The relation between serum leptin, max VO2, blood lactic acid levels before and after exercise, and effort durations of participants were investigated. At the end of the tests, no difference was found between leptin levels, max VO2 values, lactic acid values before exercise, and test durations of male type I diabetes patients and healthy sedentary males (p > .05), whereas lactic acid levels after exercise were found to be lower in healthy sedentary males (p < .05). Leptin levels in the group with BMI above 25 kg/m(2) were higher than those in the group with BMI below 25 kg/m(2) (P < .001). It was also seen that max VO2 values and test durations were higher in the group with BMI below 25 kg/m(2) (p < .05). In conclusion, leptin levels of male type I diabetes patients are close to those of healthy sedentary males. The increase in leptin levels in both groups is in proportion to the BMI of individuals.
